But on the documentary, on at 9pm this evening (Wednesday, December 6) on Channel 5, Conrad Wright says he is “troubled” by pictures of Steven Wright with estate agent Suzy, before she vanished in 1986.

Scotland Yard probed the links between Wright and Suzy – who worked together aboard the QE2 in the 1980s – but ruled him out in 2012.

But Conrad, 81, will reveal his own doubts for the first time, saying: “Amongst his photographs when he came here, was him, Steve, and Suzy Lamplugh.”

(Image: PA)

Suzy went missing aged 25 in South West London, and she was declared officially dead in 1994 – though her remains were never found.

The link with Suzy was first disclosed by Diane Cole, Wright’s first wife, who checked her diaries and found he was on shore leave when the estate agent vanished after showing a “Mr Kipper” around a house in Fulham.

Conrad adds: “There are so many questions to my mind... when you’ve got hours and days on end really, you tend to think, ‘What if? What could be?’”